There are several 'false widow' species in the UK. The one most people are generally referring to is the noble false widow (Steatoda nobilis). It has been in the UK for well over 140 years. It was first recorded in Britain in the 1870s (often cited as 1879), probably arriving accidentally on cargo ships carrying fruit from Madeira or the Canary Islands. For many decades it was largely confined to the south coast of England. Since the 1980s, it has spread rapidly across southern England and, more recently, into Wales, the Midlands, northern England, and parts of Scotland. Scientists think this expansion has been helped by milder winters, urban environments, and transport of goods. It's also worth noting that not all false widows are newcomers. The UK has six species commonly called false widows, and some, such as the cupboard spider (Steatoda grossa) and rabbit hutch spider (Steatoda bipunctata), have been established in Britain for a very long time, with some being native....
An Intimate Guide to British Wildlife